Losing pressure - can't run Liquidator

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carlscan26

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Dec 22, 2010
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San Diego, CA
Hello everybody. I have a new one for you:

I went to test the water this afternoon to see what the rains have done to my balance turns out things are pretty good: pH: 7.2, TA: 55, FCL: 2.5 - that's low since I need at least 5 with my CYA level (60) so I decide I'll add some more Cl manually and also kick up the Liquidator. I go over to the pad, pump is running at filtration speed of 1K rpm (nice and quiet) - go to open the valve on the LQ and see that the flow meter is at 0 - the indicator ball is at the bottom. Hmmm. Tap on the meter, rotate the valve open and closed, nothing. Open the LQ and the water level is low. Everything moves freely and no white build up. If I lift the suction float I get flow to the pump. I pull the pressure side line apart at the check valve and I have no flow on the pump side of the tube...drop the tube to check the connection on the pipe and it starts flowing...play around with this and find that it only flows if the line is no more than 6" higher than the pump :?:

So I figure there's something impeding flow bringing my pressure way down. The strainer basket is kind of dirty so I clean it out. Start everything back up same problem. I check the skimmer - it's clean and I'm seeing good flow into it. I check the returns - they "feel" normal but that's subjective at this flow rate. I am not losing water so no fear of a broken return pipe. I check the suction through the cleaner port instead of the skimmer, nothing changes. I change the return to go through the waterfall only - now the LQ supply has enough pressure :?: Switch it back and not enough :grrrr:

Why did this all of a sudden stop working? Is the filter dirty? The pressure gauge never registers when the pump is at this low a speed. I kicked on the solar speed and even then the pressure was only 4 lbs higher than it was when I first set it up; it's at 12lbs now. I played with speeds and I had to take it up to 1200 RPM to get the LQ filling properly.

Any ideas?
 
Can you post a picture of your LQ installaton?

The LQ should need very little positive pressure on the fill side. If you left the check valve in the line that may be part of the problem. Thise check valves have a pretty good spring in them and they need a couple of pounds of pressure to open them.
 
This doesn't really surprise me. At low fixed speeds, a variable speed pump's flow will decrease as a filter capture's dirt and offers more resistance. As you saw, when you bumped up the pump speed, the flow returned to an expected level. If you had an Intelliflow VF, the pump would have done this automatically.

Periodically running the pump up to the speed expected where a clean filter is permitting, depending on the pipe size primarily, what a single speed pump would provide in terms of flow and checking the pressure in the tank is needed to determine if it's time to clean the filter. Then you'll have a more recognizable set of parameters to make the decision.

For example, a 2 HP whisperflow and an FNS 60 filter with 2" plumbing will typically show about 16 PSI on pool. That's pushing a lot more water than in Intelliflow VS-3050 or VS-SVRS at 1000 rpm. Bumping up the speed with these pumps to about 2700 rpm should give approximately, a similar flow rate to the single speed.

Scott
 
Dave, I took the check valve off and it still didn't have enough pressure.

Scott, I turned the pump up to the solar speed (2600 rpm) and the pressure gauge had only climbed 4 lbs...shouldn't it be closer to 10-15 lbs before I need to clan the filter?

I'm wondering if maybe I have something stuck in my impeller? I wasn't very careful the last time I cleaned out the basket as I was trying to figure out why the basket was draining out so maybe something was sucked in? How do I check the impeller on one of these pumps?
 
Ok so ill check the impleller without taking the pump apart and I'll backflush the filter and see if that helps. I'll probably pop it open too since this will be my first time backflushing it (first cleaning for that matter). If things improve great. If not the I'll pull the pump apart. Here's hoping!
 
So I cleaned out the filter twice this weekend; both times I backflushed and opened the filter itself and cleaned the cartridges and filter body. The second time I weighed exactly 6 lbs of DE and mixed it with water and poured it into the bottom of the filter before I closed it up.

The pressure to the liquidator fill line was moderately better but still not enough to get up to the LQ - maybe 6" above the pump now vs at the pump before the filter cleaning. So I'll be opening the pump up this weekend and checking out the impeller. I will probably try a thin brush first though just in hopes of not cracking the pump apart.
 

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I finally had a chance to pull the wet end apart. The only thing that made it hard was the lack of space at my equipment pad.

Anyway, after opening it up I found some stuff in the impeller housing and the impeller itself - long, thin, fibrous twig-like things; kind of like the stem of a leaf if the leaf was ripped off. Didn't look like anything I have floating in the pool normally. No one vane was cloged up completely or anything like that. Three of the six had one or two of these things in them. I cleaned them out, wiped everything off, lubed the seal and put it back together. It started raining tonight so it's going to be hard to tell if I have a leak...but here's hoping :cool:

An immediately noticeable improvement: the pump primed on speed 3; it was having issues before even if I cranked it to speed 4. This time it fired up just fine :whoot:

However, the LQ is still barley flowing with the valve wide open and the pump at 1100 RPM when the suction is set to the skimmer only :rant: With suction set to the cleaner it gets up to 2. Split between both its getting to 3-4. I never watched it on cleaner mode as that runs early in the morning so I can't say if 2 is normal or not. However the skimmer mode is definitely not normal. So I'm thinking I may have a partial clog in the skimmer line since its looking fine when I have it suctioning from both the cleaner and the skimmer? Factor in the past need to prime with a hose in the skimmer...this seems pretty likely right?

I'm going to try the hose with a rag tomorrow (ran out of daylight today). The only way I see doing this without taking the jandy valve apart is through the pump basket opening to the suction line...but I've got the jandy valve and then a 90 degree and a 45 degree to the skimmer line...will these three pose too much of an obstacle for the flush? Should I try flushing from the skimmer to the pad instead? I have really strong pressure at the nearest hose - I think it's tapped into the main before the regulator to the house.

As always, your advice is much appreciated :cheers:
 
So yesterday I tried flushing out the line with a Drain King - opened the pump basket and did it through the intake opening. It was pretty noisy and sprayed back a little but not too bad. I barely felt any water at the skimmer. Leads me to believe that the backflush was not effective or that I need to take the suction valve apart and feed more directly into the skimmer line or that I have a more serious blockage than I thought.

So I guess the next step is to snake the line...

Side note/question: when I pulled out the DK, I was surprised to se that it was just a thin stream of water coming out - this was with the water turned off, but is it possible that mine is defective?

At high speed for solar everything seems to run fine so maybe I'm going to have to accept it and run the pump higher for the LQ; it just bugs me that it used to work and I hate not figuring it out.
 
carlscan26 said:
Side note/question: when I pulled out the DK, I was surprised to se that it was just a thin stream of water coming out - this was with the water turned off, but is it possible that mine is defective?
Click to expand...

The drain king isn't a high flow deal. It pressurizes the line, but doesn't have a high flow. Both ways have merit.
 
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